142 



lead produced could be attributed to an undue overflow of the 

 sump. Care was also taken to exhaust the fuel burning in 

 the hearth of all the lead furnished by the ore employed for 

 producing a running sump, before any of the ore to be experi- 

 mented on was thrown into the fire; and the same caution 

 was observed in exhausting the fuel of its lead at the conclu- 

 sion of each experiment. The fire left at the end of one pro- 

 cess was used as fuel at the beginning of the next. 



" All these preliminaries being arranged, and a running 

 sump established, ore from one of the heaps was thrown on 

 the fire at intervals; lime was occasionally sprinkled on to 

 thicken the slag; and the smelting was continued in the usual 

 manner, with a good blast, well circulated, until the whole ton 

 had passed through the furnace, and the first run obtained. 



" The slags were then transferred to the slag-hearth, and 

 again smelted. The second slags were neglected, although 

 in the great smelting-houses they are ground in a crushing- 

 mill and huddled, and lead in grains is obtained in remunerat- 

 ing quantity. I had not means at my disposal for doing this, 

 and hence my produce appears to a slight disadvantage. The 

 ashes with which the slag-hearth had been filled were bud- 

 died, and some lead in small lumps procured. Both heaps of 

 ore, viz., the soft and the hard, were subjected to the same 

 treatment, and their lead extracted. 



" I now proceed to state the cost of smelting one ton (of 

 2240 lbs.) of refractory ore, cut from a hard rock, laid down at 

 the blast-hearth. 



s. d. 

 Coals, carriage included (2 cwt.), .... 3 



Coke, &c., 2 1 



Lime (2 cwt.), 2 



JL 



Turf (156 sods), 7 



Wages of ore-smelter, at I3s. per ton of lead, 6 7 



Wagesof slag-smelter, at 70*. per ton of lead, 2 6 



16 9i 



